Seaweed is the new algae of biofuels

Lauren Craig EarthTechling, 28th January 2012

We've certainly been hearing a lot about algae as a biofuel feedstock.

But now, a team of scientists from a privately-held lab in California have developed a breakthrough technology they claim will enable advanced biofuels and renewable chemicals to be manufactured from macroalgae—more commonly known as seaweed.

The process, developed by Berkeley-based Bio Architecture Lab (BAL), works by first transforming seaweed into a renewable chemical intermediate, and then producing chemicals or fuels through chemical synthesis or fermentation.

According to BAL, aqua-farmed seaweed is the "world's lowest cost, most scalable, and sustainable source of sugars for biofuels and renewable chemicals production."

And, in truth, seaweed overcomes many of the challenges facing commercial production of advanced biofuels. For one, like algae, it has no lignin – the chemical compound that makes veggies, plants and wood firm – and is highly resistant to the enzymes necessary to unlock the sugars in cellulosic biomass. It also has high sugar content.

However, according to Biofuels Digest, algal biofuel production has its own challenges, which some think could be addressed by transitioning to seaweed as a feedstock. First, there is the issue of getting the algae out of the water it grows in—this is much trickier than removing seaweed from the water.

Second, after extracting the lipids from algae, biofuel producers are left with a ton of residual biomass, which must be disposed of somehow—often, by burning it, or feeding it to cows. Either way, the water and the waste must be transported. This fact leads some critics to argue that the amount of fossil fuels that go into producing biofuels from algae make it an unsustainable biofuel feedstock.

Like algae, seaweed also has the advantage of not requiring arable land to grow. However, unlike algae, seaweed does not require freshwater to grow, and it produces a lot less residual biomass. Further, we already know how to farm it. Commercial-scale production of seaweed is already underway in many parts of the world, including Chile, where BAL has four seaweed farms.

The company was awarded a grant from the U.S. Department of Energy's Advanced Research Projects Agency – Energy (ARPA-E) to develop a process to convert sugars from seaweed into isobutanol. According to ARPA-E Program Director Dr. Jonathan Burbaum, "BAL's technology to ferment a seaweed feedstock to renewable fuels and chemicals has suggested an entirely new pathway for biofuels development," he said.

"When fully developed and deployed, large scale seaweed cultivation combined with BAL's technology promises to produce renewable fuels and chemicals without forcing a tradeoff with conventional food crops such as corn or sugarcane."

In addition to ARPA-E, BAL's technology is also supported by the Concurso Nacional Grant provided by InnovaChile CORFO, and the Norwegian oil giant Statoil. The technology was recently featured in the Jan. 20 issue of Science magazine.

Interestingly, researchers at Clemson University have also identified the alginate in seaweed as a promising substitute for the toxic compounds used to manufacture binder material for lithium-ion battery electrodes. They believe that using the alginate-based compound could also boost battery storage capacity.